Endoscopic diagnosis of peripheral lung lesions: Bronchoscopic techniques and cell free tumor DNA

Research output: ThesisPh.D. thesis

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Abstract

This PhD research explores strategies to enhance the diagnostic yield of bronchoscopy in the diagnosis of suspected lung cancer patients. Lung cancer stands as the most prevalent and fatal cancer in Denmark. In its early stages, lung cancer is often incidentally discovered as a small lesion on a chest scan. These lesions can be either benign or malignant, necessitating a tissue sample for a definitive diagnosis. While bronchoscopy, an endoscopic examination, carries a low risk of complications, pinpointing the lesion and ensuring accurate tissue sampling can be challenging.

Various methods have been devised to address this challenge. One such method involves using a small ultrasound probe inserted via the bronchoscope into the lung tissue, capable of differentiating between air-filled lung tissue and consolidated tumor tissue. Another method, electromagnetic navigation bronchoscopy (ENB), assists in navigating the airways. The chest scan is initially employed to plan a route to the lesion, and during the procedure, this route guides the bronchoscope to the intended location.

In Study I, a systematic literature review was conducted to assess whether combining ultrasound with ENB was more effective than ENB alone. Although some studies presented a direct comparison, results were inconsistent. While an RCT study demonstrated improvement with ultrasound, other findings contradicted this, and there was a lack of consensus on outcome definitions.

Study II, a pragmatic randomized controlled trial, compared patients receiving ENB alone to those receiving ENB + ultrasound. Contrary to expectations, no significant difference was demonstrated between the two groups. Moreover, only half of the procedures resulted in a conclusive diagnosis. However, the study affirmed the safety of bronchoscopic procedures.

In Study III, we investigated the feasibility of detecting cancer cell DNA in bronchial lavages obtained during bronchoscopy to determine the malignancy of lung lesions. Both bronchial lavages and blood samples were collected. While bronchial lavages more frequently contained tumor DNA and provided more accurate results than blood samples, not all cancer patients exhibited tumor DNA in the lavages, and tumor DNA was also found in patients without cancer. 

From the findings in this thesis, it is evident that there is a general lack of evidence regarding the yield of current methods. However, the results from Study II suggest that the yield may be lower than anticipated. Although tumor DNA cannot yet serve as a sole diagnostic tool, further studies on the use of bronchial lavages should be pursued, as they appear to be more accurate than blood samples for diagnosing lung cancer." 
Translated title of the contributionEndoskopisk diagnosticering af perifere lungeinfiltrater: Bronkoskopiske teknikker og cellefrit tumor DNA
Original languageEnglish
Awarding Institution
  • University of Southern Denmark
Supervisors/Advisors
  • Laursen, Christian Borbjerg, Principal supervisor
  • Hilberg, Ole, Supervisor
  • Rasmussen, Torben Riis, Supervisor, External person
Date of defence26. Jan 2024
Publisher
DOIs
Publication statusPublished - 14. Dec 2023

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